1. Field of the Invention
The present invention relates to torquing systems. More particularly, the present invention relates to an improved torque hydraulic torque wrench system which includes various improvements for extended life and control of applied torque.
2. General Background of the Invention
Hydraulic torque wrenches are wrenches which are utilized in numerous industries requiring the tightening down of nuts with a very high torque in the magnitude of as high as 50,000 foot pounds. A particular line of wrenches, known as torque wrenches, have been developed, which are usually hydraulically controlled, and incorporate a ratcheting mechanism where the wrench can be hydraulically operated in order to achieve the high torque, yet operate as a ratcheting wrench in a more confined area.
U.S. Pat. No. 5,097,730, entitled “Inline Ratcheting Tool,” incorporated herein by reference, explains the operation of a hydraulic torque wrench. U.S. Pat. No. 4,201,099 issued to Junkers, entitled “Hydraulic Wrench”, incorporated herein by reference, discloses a piston type hydraulic wrench comprising a housing having a first portion and an elongated second portion integral with the first portion and forming a cylinder. Shown is a piston reciprocable in the cylinder, and a shaft having an axis extending transverse to the cylinder and mounted in the first housing portion with an end portion of the shaft projecting outwardly from the housing, and a piston shaft connected at one end to the piston, and at least one drive lever mounted in the region of one end turnable about the axis of the shaft means and connected at the other end of the piston shaft. This connection operates a ratchet wheel during operation. A review of the '099 patent as seen particularly in FIG. 4, indicates that during operation the piston shaft must move from its position transverse to the axis of the ratchet member. During such movement, a change occurs in the 90 degree relationship between the rod and the axis of the ratchet adversely impacting the wrench's torquing power and leading to a shortened wrench life.
Various problems exist with prior art wrenches. One problem includes the tendency of the drive pin, connecting the piston shaft to the ratchet member, to wear against the body of the torque wrench requiring replacement/refurbishing of the body portion.
Another problem includes the drive pin being deformed during use (by the high forces) required by operating conditions.
Another problem includes the drive pin being contacted by a relatively small surface area and increasing irregular localized deformation.
Another problem includes excessive variations in the applied torque during piston stroke.